This invention relates in general to force-supplying devices for straightening and pulling unitized car bodies. More specifically, the invention relates to straightening of automobile bodies of the unibody type by the use of a lightweight rectangular frame which is attached to the underside of the vehicle at the four corners of the frame by individual clamping means. The clamps grip the pinch welds which run along both sides of the vehicle body approximate the outer edge. After the frame has been clamped to the vehicle, conventional force-transmitting devices such as cylinders, lever arms and chains are attached on the frame at various attachment points so that the body can be pulled or pushed, depending upon the precise damage.